Hello Everyone! This is my first post!

I was hoping you guys could help me.

I have been having troubles with my car not starting when it rains. It just cranks and cranks. Sometimes if I'm lucky the car will start and then die 5 seconds later.
When the sun is out or it warms up, my car starts right up without any problems!!

Here's the situation...
I recently bought the car and replaced the alternator. After this started happening I replaced the spark plugs, air filter and battery. The distributor cap doesn't have any moisture/cracks/etc. The coil is dry.
I have been leaving my alarm off and I do not see any disconnected vacuum hoses. I have sealed off my sensors with silicone to prevent moisture getting in and the ECU doesn't have any water or moisture on it when it rains but the tape wrapped around the wires is a little sticky. The battery cables look great and do not see any broken areas.

Here's the interesting part. ...

Yesterday I get in my car (covered in water from the rain) to start it and it doesn't start. I keep trying... just cranks but no start. I turn on my windshield wipers to full (just for the heck of it) and they slowly move. Then get faster and faster and eventually get up to full speed. I turn them off. I try the key again and the car starts! This has happened a couple of times.
One time my car started right up but once I turned the winshield wipers on it died and wouldn't start afterwards. I disconected the battery and reconnected it then tried... nothing. I turned the wipers on and off again, tried the key and the car started!

I don't have any problems during normal driving if I use the wipers.

There is a gap between my hood and my windshield and you can see my battery and the plastic cover over my windshield wiper motor. The plastic cover has cracks in it but the wires do not appear to have any water on them.

Any ideas?

Thanks everybody!

 

Don't know if this is a coincidence or not but today my car wouldn't start so I tried the windshield wiper trick but it didn't work. I tapped on my ECU and then my car started.

 

I was working on my car just now and cleaning ground wires. It was starting to get dark fast so I decided to stop working on my car for the day. As a test I made sure that my car still started so I started it up.
With the engine on I popped the hood to take a look and moved the distributor cap left and right. ... Then I saw it. a little white spark that I hadn't seen before on one of my spark plug wires. It was a very faint spark but noticeable because of the darkness. It was flickering randomly. I've never seen this before!

I have been in denial about replacing my spark plug wires because they cost $150 on bimmerparts.com. It looks like this may have been the culprit the whole time.

The weird part is that my spark plug wires have a cover thing that slides around. It must have been covering the hole up before.

What do you guys think?

 

I think you need new wires.

 

I would guess it is a ground problem. There is one on the rear of the engine that grounds to the body. Take it loose, clean it and put it back on, of course check condition. There is another ground at the rear of the car, inside the hatch, behind the spare tire thingie. It is a brown wire, and it causes lots of problems, clean it also.. Ground problems in a 944 are common, and will cause you to go batty.

My car used to quit when I hit a bump. Drove me nuts for about a year. It turned out to be loose plates in the battery. When I hit a bump, the plates would shift, and ground out the battery. Like to have never found that.

Bad grounds can trash the brain, so find it as soon as you can.

Bill Seifert

1987 944S Race Car

 

I'd say you should go with new cap / rotor and plug wires. You problem is pretty common for a car with that needs a tune-up.

 

Today my car was covered in snow and it wouldn't start. I tapped the ECU while turning the key and it started right up. I think I'm going to tear this thing open and check the solder connections.

I am also putting in new spark plug wires today.

 

Kevin, be careful doing that, those things cost $200=$400. The car that I saw that had that happen, was just the plug to the ECu wasn't going all the way in.

Bill

 

I just wanted to post an update on this thread for anyone else having the same problem.

For the past few weeks it has been very cold outside and I have been unable to start my car. After trying quite a few times I tap on the ECU while starting my car and it starts right up. I have put it all back under the passenger side footwell and just tap the floor board with a screwdriver while turning the key when it doesn't start and it starts right up.

Here is what I'm thinking. There is a bad solder somewhere in the ECU. When it gets cold outside this causes the solder to shrink away from it's joint and creates a gap. This is a theory however. I haven't had the chance to open my ECU yet but I will do it eventually and let everyone know the results.

I may possibly replace the ECU but has anyone on here re-soldered their ECU connections? Any horror stories? Is is fairly easy with solder experience?

Thanks everyone!